Drill head



Dec. 11, 1934.. 1.. c. HARDSOCG 1,983,798

DRILL HEAD Filed April 24, 1933 Patented Dec. 11, 1934 PATENT OFFICE DRILL HEAD Lester C. Hardsocg, Ottumwa, Iowa, assigncr to Hardsocg Manufacturing Company, Ottumwa,

Iowa

Application April 24, 1933, Serial No. 667,685

5 Claims.

This. invention relates to that class oi drills which are commonly employed in coal mines.

The objects of my invention are to provide a drill of this class of simple, durable and inexpensive construction so arranged that three drill bits may be used on each side of the drill head, and each bit firmly and securely held in position for use by wedging action applied to all four sides of each bit.

A further object is to provide a drill of this character in which on each side of the drill head there are employed two bit wedges arranged side by side, and so arranged that when the wedges are being driven to position for securing the bits, they will alwaysstand in line transversely so that equal wedging pressure is applied to each bit.

A further object is to provide a drill or this character in which the projecting ends of the drill bits are protected and reinforced, and also provided with means wherebythe bits may be successfully and advantageously employed after they have been worn or ground down to a considerable extent.

My invention consists in the construction, arrangement and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawing, in which:

Figure 1 shows a side elevation of a drill head embodying my invention.

Figure 2 shows a side elevation of two adjacent wedges.

Figure 3 shows a transverse sectional view on the line 3-3 of Figure 1.

Figure 4 shows a longitudinal sectional view through one of the drill head sockets, showing the wedges and bits.

Figure 5 shows a side view of a modified form of wedge for utilizing bits of different lengths.

Referring to the accompanying drawing, I have used the reference numeral 10 to indicate generally the body portion of the drill head and havingthe usual spiral flange thereon for removing the pulverized coal after it has been cut by the bits. 7

The bit head is indicated generally by the reference numeral 11 and is provided on each drill head, and the side faces of this opening are slightly curved, as shown in Figure 3.

V The opening is also tapered at its narrow sides, as shown in Figure 4, so that it is widest at its outer end. The drill head beyond said openings is formed with a segmental wearing block 12, being centered at the center of the drill head and being projected laterally to an extent somewhat wider in diameter than the general width of the spiral rib on the body portion 10. v

The advantage of this segmental wearing block is that in the event that the outer bit should become broken or worn, and the drill head in its progress through the coal should irictionally engage the coal, these segmental wearing blocks will withstand a very considerable amount of wear before being worn oil enough to interfere with the firm securing of the bits and wedges in the said openings.

The bits are of the usual construction, and are indicated generally by the numeral 13. They are preferably rectangular in cross section and sharpened at both ends, and slightly curved longitudinally as clearly shown in Figure 3.

For firmly and securely, and at the same time readily detachably, holding these bits in the openings in the drill head, I provide for each opening two wedges each indicated generally by the reference numeral 14. These wedges are each tapered transversely in both directions, the side. taper being shown in Figure 2 and the end taper being shown in Figure 3, and they are also preferably slightly curved from the outer to the inner end, as shown in Figure 3, to lit the contour of the curved interior of the openings in the drill head.

On each wedge on one of the wider faces thereof is a longitudinal rib 15. The outer side of the rib at 16 is tapered downwardly and toward the center of the wedge, and the other edge of the rib 1'7 is substantially parallel with the inner face of the wedge, as shown in Figure 2.

Formed in the wedge adjacent to the lower end of the rib 15 is a curved shoulder 18, one on each side of the rib 15. This shoulder is shaped to receive and fit the contour of the adjacent end of the bit when placed in position. On the two adjacent sides of the wedges I have formed on one side thereof a lug 19, and a coacting notch 20, so arranged that when the two wedges are placed side by side these lugs and notches will interlock and hold the two wedges in alinement transversely and yet permit a slight lateral movement of both wedges toward and from each other.

In the modified form shown in Figure 5, I have shown a wedge in which the shoulder 18 on the outer side of the wedge is located somewhat higher up on the wedge than is the corresponding shoulder 18 of the other wedge.

In practical use it will be seen that all of the parts are of simple and inexpensive construction. To apply the bits to the drill head, I first place two of the wedges 14 in side by side positions, and then place three bits 13 in position within the spaces adjacent the ribs 15. The width of the central bit and the corresponding positions of the adjacent edges of the wedges is such that when thus assembled the wedges will be slightly spaced apart.

Then this assembly, which can be conveniently and easily held in the operators hand, is inserted' in one of the openings in the drill head and the wedges are then driven down into the opening until they frictionallyengage the walls of the opening firmly enough to hold the assembly in position.

During this driving movement it is obvious that the wedges will drive the front faces of the bits firmly against the front side wall of the opening. The wedges will also frictionally engage the backs of the bits, and firmly hold them against movement rearwardly. Furthermore the two outer bits are wedged between the bodies of the wedges and the adjacent outer and inner walls of the opening and the center bit has both of its side edges wedgingly engaged by the two wedges, so that in this assembly all four sides of each bit are wedgingly engaged and held against movement.

By having the upper ends of the wedges projected to a considerable extent beyond the end of the drill head, and in engagement with the backs of the bits, it is obvious that these wedges form braces and supports for the bits, and serve 'to a great extent in preventing the bits from being broken oiT or bent when they strike a solid construction.

In practice I have found that a considerable advantage is gained on account of that part of the construction described, which consists in ribs 15 on the relatively wide wedges, which ribs strengthen and reinforce the wedges so that that part of the wedge which projects beyond the head of the drill, and which engages the back or the follow side of the drill bit strengthens and reinforces the drill bit and prevents it from being broken off or bent back when the drill bit strikes hard objects or excessive pressure is otherwise applied to it.

With the wedges shaped to engage the backs of the bits beyond the drill head and reinforced by the ribs 15, then the transverse diameter of the wedge as a whole is substantially greater than the corresponding transverse diameter of the bit, so that the bit is thereby strengthened and reinforced.

In connection with the modification shown in Figure 5, I have found this to be very useful in connection with the utilization of bits that have become worn and ground off until they are sub-- sponding shoulders 18 of the other wedges, and when the operator has bits which have been worn and ground considerably shorter than the original bits, he substitutes one or more of the wedges of the kind shown in Figure 5, for the other wedges, and is thereby enabled to utilize successfully the shorter bits. Obviously some of the wedges may have all of its shoulders 18, or

one of them, adapted for use in connection with shorter bits.

I claim as my invention:

1. In a drill the combination of a drill head having a tapered opening, two wedges seated in said opening side by side, each wedge having a flat face and being formed with a rib projecting outwardly from said flat face and a bit mounted in said opening between and inengagement with the ribs of the said wedges, and whereby when the wedges and bit are forced into said tapered opening the side edges of the bit are clamped between said ribs.

2. In a drill, the combination of a drill head having an opening therein, two wedges shaped to be forced into said opening, each wedge being formed with a longitudinal rib, and a bit mounted in said opening between and in engagement with the ribs of said wedges, and whereby when the wedges and bit are forced into said tapered opening the side edges of the bit are clamped between said ribs, said parts being so shaped and proportioned that when assembled and inserted in said opening said ribs will wedgingly en age opposite sides of the bit and said Wedges and the adjacent wall of said opening will wedgingly engage the remaining sides of the bit.

3. In a drill, the combination of a drill head formed with a tapered opening, two wedges mounted in said opening, each wedge being formed with a longitudinal rib, and three bits, one of said bits being inserted between and engaged by said ribs on opposite sides and the other bits being engaged on opposite sides by one of said ribs and the adjacent wall of said opening.

4. In a drill, the combination of a ,drill head formed with a tapered opening, two wedges mounted in said opening, each wefdge being formed with a longitudinal rib, and three hits, one of said bits being inserted between and engaged by said ribs on opposite sides and the other bits being engaged on opposite sides by one of said ribs and the adjacent wall of said opening, and each of said bits having one side in engage ment with one of said wedges and its remaining side in engagement with the adjacent wall of said opening.

5. In a drill, the combination of a drill head,

movement of the bits, one of said shoulders being nearer the outer end of the rib than the others, to thereby hold a relatively short bit with the outer end substantially in line with the, outer ends of the other bits. T

LESTER C. HARDSOCG. 

